The workhorses of NASA's last few decades in space are showing their age.

Last week the space shuttle Discovery took a victory lap around Washington D.C. as it enters retirement. And it was 22 years ago today that Discovery carried with it into orbit the Hubble Space Telescope, which has now spend two decades-plus sending back piles of data and amazing images from space.

Indeed, the 22nd birthday is a tough one. For Americans, it can't quite match the all-out blowout of the 21st birthday, and for Hubble, it's one year closer to planned obsolescence. Well, maybe. After a shuttle servicing mission a few years, Hubble is now slated to run at least into next year and perhaps beyond. And Hubble's would-be success, the James Webb Space Telescope, has been bogged down with delays and threatened with funding cuts.

So, for now, Hubble's hits keep on coming. In 2010 NASA released an IMAX documentary about the telescope and its work called Hubble 3D. And a new breed of space telescope is ready to push the boundaries of space exploration as Hubble winds down its life.

If you'd like a heavy dose of Hubble trivia, check out this post at Bad Astronomy. Or, if you'd like to kill your Monday afternoon clicking through 22 years of mind-blowing astronomical imagery, head over to the Hubble gallery.